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Recently, a lot of friends contacted me about rumors with the new 5G cell phone technology. Various rumors floating around, such as, it causes cancer, or other illness, causes problems with airplanes and radios, or the technology is dangerous in other ways. Unfortunately, the sources of these information always lack every aspect of basic competence in any sort of engineering or technology, even the news in the media lack the basic scientific knowledge to discuss this topic. I am, by no means, expert in radio technology, however, i will try to explain what is going on with 5G, what are the real issues with the technology (if there is any), and what are dangers of this technology.
GSM was the first widely used phone signal standard, developed in Europe, and it was first deployed in Finalnd. It used the 800MHz, 900MHz or the 1800 MHz bands, depending on the country. The initial technology only supported voice connectivity, as it was a dumb protocoll. A popular data connection standard was added to the GSM standard in the early 2000s. The first (widely available) iteration of this was the GPRS (GSM 2.5). Later on, the protocoll was redesigned, and renamed EDGE (GSM 2.75) which can offer higher internet speeds. GPRS supports up to 5 KByte/sec, EDGE can do 48 kbyte/sec.
For personal usage, the WiFi was released in 1997, first using the 2.4GHz frequency. Nobody used it for quite a while. It was originally offering 2 MBit/sec bandwidth (256 kbyte/sec). The 802.11b standard of the WiFi, which was the first one with mass adoption, offered 11 MBit/sec (about 1.3 MByte/sec), and the 802.11a, using the 5 GHz brand, offered 54 MBit/sec.
As we can see, the data throughput of the 5 GHz standard is bigger than the 2.4 GHz standard. Smaller the frequency is, slower the communication might gets. Imagine someone turning on and off a flashlight, it will take a while to send a morze-signal with it. However, if some computer turns on this flashlight tousands of times on and off, the communication becomes faster. Then you may say: oh, then larger the frequency is, faster the communication is. Well, not quite. There are serious drawbacks, when using higer frequencies.
Lets see our example: turning on and off a flashlight on the top of the mountain: everyone can see it, ever from a larger distance. However, the faster the communication gets, less noticable it will be. The same happens with radio and cell phone communication. You can receive LW frequencies on your radio from another countries, and even you can operate such a radio cheaply. However, the higher audio quality FM radio stations needing several transmitter antennas in basically every larger cities, and they qucikly cutting off after a specific distance.
In the case of using a good WiFi router, and a device with good WiFi connection, the 2.4 GHz WiFi signal can be easily received even by your neighbours, however, when using the 5 GHz standard, the coverage quickly drops after a few meters. The following illustration explains the expectations, when using the same router (that uses the same antenna and wattage) with the 2.4 GHz and 5 GHz WiFi standards:
Green means good signal, yellow means degraded signal, red means low quality signal.
We can observe that the 5 GHz version of WiFi travels about half as far as the 2.4 GHz signal. The same is ture for radio and mobile communication stations as well, lower the frequency is, further the signal travels.
To encounter the loss of signal distance, various tricks can be used. One of them is directional antennas, which air the radio signal to only one direction. The another trick is to increase the signal strength. A typical 2.4 GHz WiFi device uses 17 or 19 DBm (0.05 or 0.075 watts). Stronger routers can be set to 23 or 24 DBm (0.2W or 0.25W). The strongest routers can be set to 27 DBm (0.5 Watts), but this is beyond legal limits, and will probably not result better coverage, as the device must also be able to communicate back to the WiFi hotspot, so solving the problem alone with was muscles, will usually not help. WiFi can not be set below 2.4 GHz, because thats the legally usable frequency for unlicensed civil usage. WiFi has only a few sub-bands, because for such low frequencies, its not possible to have a lot of communication channels. If someone wants more than a few meters of coverage, basically he has to use the 2.4 GHz WiFi standard instead of the 5 GHz standard.
GSM was replaced by the 3G mobile standard, which allows for 800-900 KByte/sec download speeds (6 MBit) with the latest HSPDA standards in theory, and 100-200 KByte/sec upload speeds. In reality, 1-2 MBit can be expected. Of course to achieve the high data rates, a network operated on 2100 MHz is required with 3G, for example a 3G operated on 900 Mhz will not be notably faster than EDGE.
When comparing these speeds to cable-based internet speeds, which can easily exceed 100 MBit/s, or even 1 GBit/sec nowadays, we can see that there is indeed a need for high-speed mobile internet. However, this is not possible without increasing the frequency significantly upwards. If you even wondered, why your cell phone reverts back to EDGE from 3G when you travel to villages or outskirts of cities, this is the main reason.
To get higher data rates on portable devices, newer standards are required, with higher frequencies. 5G uses 24 or 54 GHz frequency, which is one magnitude higher than the previous standards. The new 5G standard have an option to be implemented on 900 MHz as well, but this low frequency is not being widely used, because the higher data rates couldn't be achieved with it. Extensive use of signal repeaters will have to be used to supply wide coverage for the new system.
Low frequencies, such as the 800-900 MHz signal of the GSM, can easily penetrate through walls, trees, and objects. Above 2.4 GHz, this is becoming increasingly problematic, as higher frequencies - such as 5 GHz WiFi - barely can penetrate walls. Compared to 4G, these high frequency 5G towers requiring enormous energy to operate, and they will still need far more: one repeater will have to be installed basically on every street, to have coverage.
Rural regions are notorious for bad cell phone coverage, for example, in my location we only have a stable 3G available since 2021 october (and this standard was introduced about 15 year ago). With GSM, one large radio tower was enough for a region, with 5G, rural regions will not be covered. Most countries started to end the 3G network, which means that places like mine, will be left with EDGE network again, and 5G coverage seems totally impossible.
There is a misinformation, saying, 5G disturbs the airplane communication network. 5G doesn't disturbs the communication, it actually disturbs the weather radars and height altimeter radars. As higher frequencies can't effectively penetrate objects, high frequencies are used to detect weather conditions, ground heights, which will interfere with the signal of 5G equipment placed all over the cities. This means that airplanes sometimes can't use their own radars to avoid dangerous build ups of clouds and weather events, mountainous regions, which makes the flights less secure.
Some frequencies were linked to cancer development by previous studies. Very high frequencies can cause cancer, however, the frequencies used by 5G is lower than that. Other health effects, however, to those, who live near to a 5G repeater, can be expected, if the repeater is closer to them than 3-4 meters. Tiredness, sleep problems can occur, if the exposure to these devices are present in long-term.